Fastener



FIG. 1 is a front elevational view of a fastener showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is an inverted rear view thereof.

FIG. 7 is a top perspective view thereof. 

The ornamental design for a fastener, as shown. 